The instant invention relates to stethoscopes and the like and more particularly to a novel construction for the microphone portion thereof.
Stethoscopes have for years been one of the primary instruments relied upon by physicians in diagnosing and detecting certain types of ailments in patients. The microphone portion of a stethoscope is positioned in engagement with a portion of a patient's body and the physician is able to listen to the sounds emanating therefrom, to enable him to make his diagnosis.
Traditional stethoscope microphone constructions have included a head member with a diaphragm attached thereto which vibrates in response to sound waves when positioned in engagement with a patient's body. As the diaphragm vibrates it causes compression in a cavity in the microphone and the compression is transmitted through tubular members to ear pieces which are positionable in the physician's ears. Previously known diaphragm type microphones have not been completely effective throughout the entire frequency range of sounds normally associated with the human body and consequently combination stethoscope microphones have been available which have combined a bell type microphone with the conventional diaphragm type microphone to extend the range of the microphone to cover very low frequency vibrations. An example of this type of device is shown in the U.S. Patent to LITTMAN, No. 3,108,652.
While it is certainly important to provide a microphone which will detect sounds and vibrations in all of the frequency ranges normally characteristic of sounds emanating from the human body, it is also important to provide a microphone which produces a clear, audible signal. One of the main deficiencies of previously known diaphragm type microphones has been their inability to produce a clear signal as a result of secondary vibrations created between the diaphragm and the head portion of the microphone. In conventional microphone constructions the diaphragm has been secured to the head portion by crimping or pinching a portion of the head, but no matter how effectively this is done, independent secondary vibrations tend to develop in the diaphragm. As a result, the signal which is produced is not always distortion free and may not always give the physician a clear indication of the patient's condition.
The instant invention overcomes these and other drawbacks by providing a stethoscope microphone having a diaphragm which is capable of faithfully following the heartbeat or other vibration in the patient's body to provide a clear accurate transmission thereof at a level which is easily audible. Consequently the microphone can detect sounds and vibrations throughout the entire frequency range of sounds normally associated with the human body thereby providing a substantial improvement in the art of stethoscope microphones.